The speed at which data can be transmitted wirelessly has significantly increased over the past few years. Even with the advancements made in wireless data technologies, however, there still remains a need to continue to bridge the bandwidth gap that exists between wire-line and wireless data networks. Wireless networks using IEEE 802.11 (a, g, or n) standards have considerably improved data-rates in Wireless Local Area Networks (“WLANs”). These standards, however, have provisions that would allow multiple orthogonal channels to be used by different networks operating in the same vicinity simultaneously. The orthogonality of the channels allows the channels to be used simultaneously both in time and space without the concern of interference. Similarly, other wireless standards such as Bluetooth, WiMax, IEEE 802.15.4 (Zigbee) etc also allow for multiple orthogonal channels to be used. Thus, systems and methods that could make use of the multiple orthogonal channels could greatly increase the throughput in wireless networks. Unfortunately, conventional systems have not been able to make efficient use of the available orthogonal channels to achieve high data-rates.
If a wireless network array has two wireless nodes each having N radios capable of transmitting and receiving data Y Mbps, then that network has could ideally have a throughput of N×Y Mbps. For example, if each wireless node has 12 collocated radios corresponding to 12 channels in the 5.2 GHz frequency band, and each channel has a throughput capability of 40 Mbps, then the wireless network could ideally have an aggregate throughput of about 480 Mbps (40 Mbps×12 channels=480 Mbps) when all channels are used simultaneously to transmit and receive data. The actual throughput of such conventional systems, however, is about 70 Mbps, which is merely 15% of the ideal throughput. FIG. 1 illustrates variations in the aggregate throughput of conventional systems as a function of the number of simultaneous links active at the same time as compared to the ideal throughput of such conventional systems.
Two phenomena, which both pertain to the close physical proximity of the collocated wireless radios in the wireless network array, cause the unexpected performance degradation in conventional Wi-Fi array systems. First, Out-Of-Band (“OOB”) emission of energy at a transmitting radio is strong enough at relatively short distances that it can trigger carrier sensing at a nearby collocated radio operating on an orthogonal channel and also corrupt the reception of packets at the other radios if they are receiving. Second, filter inefficiencies, which occurs when two radios in close proximity are operating on orthogonal channels, also increases the effective bit error rates and further lowers performance.
Thus, there is a desire for devices that use the multiple orthogonal channels in wireless networks simultaneously to realize a high data-rate wireless link and, hence, cater to applications requiring high bandwidths. For example, given that there are 3 orthogonal wireless channels in the 2.4 GHz band and 12 orthogonal wireless channels in the 5.2 GHz band, there is a desire for a pair of devices, each equipped with 15 wireless radios, capable of using all the available orthogonal channels simultaneously to achieve a high data-rate wireless link. Further, there is a desire for these systems and methods capable of implementation as a software module that works with any off-the-shelf wireless radios, thus requiring minimal to no changes to the hardware or firmware of the radios themselves.